Added the catalogue models and seed to support phase 5 of the POC prototype in the Persistence package.

Packages/Persistence/Sources/Public/Enumerations/ShopError.swift

@@ -0,0 +1,7 @@
+/// Why a shop could not be opened.
+public enum ShopError: Error, Equatable, Sendable {
+    /// The account already owns a shop.
+    case alreadyOwner
+    /// Another shop has the handle.
+    case handleTaken
+}